Project Winter Rebirth
by BatTitan
Summary: "He first meets her once he's escorted back into the facility he had just escaped from, his head reeling from the neon colors of Times Square and the revelation that he's been asleep for seventy years." In which Steve somehow ends up adopting a girl with no name. Takes place during and after the events of The Avengers and CA: TWS. (Stucky, if you squint)


**Project Winter Rebirth**

* * *

He first meets her once he's escorted back into the facility he had just escaped from, his head reeling from the neon colors of Times Square and the revelation that he's been asleep for seventy years. He barely notices the teenage girl until she's quietly escorting him back to his room, too caught up in the fact that nearly all of the people he knew are probably dead.

"Director Fury would like me to inform you that an apartment is being set up for you and you can move in within the week, Captain," the girl says once he's inside the room, lingering at the door. Steve finally looks at her for the first time and then finds himself just staring.

She has blue eyes and dark brown hair, her mouth full and her skin pale. The ends of her hair curl a little, but the rest is pin-straight, and he can't help but notice that there's an aching similarity in the sharpness of her gaze, despite how young she looks.

He notices that she's raising an eyebrow now, catching his stare.

"Thank you," he manages to croak out and something in her expression softens marginally as she nods stiffly, turning to leave. "Wait." She turns again to acknowledge him. He wants to tell her she looks impossibly familiar, explain why he'd been staring, but what comes out is, "How old are you?"

The girl blinks before she snorts all of a sudden, surprised by the unexpected question. "Old enough," she answers simply and leaves Steve alone.

* * *

"Oh." Steve turns from where he's pummeling a punching bag at the sudden voice, the momentum from his last swing sending it flying across the room. The teenage girl from the previous week starts, wide-eyed, as the bag hits the wall and breaks, sand spilling everywhere. "Should I come back later?" she blurts out.

"No, I'm just about done," Steve reassures her quickly before she can bolt away like she looks like she wants to, starting to unravel the strips of cloth around his knuckles and dragging his wrist across his sweat-dampened forehead. "Hi again."

"Hello, Captain." She inches into the gym, eyes still darting between him and the punching bag nervously.

"Steve," he corrects and the tension in her shoulders eases slightly.

"Steve," she repeats and Steve waits a moment, but she doesn't offer her own name.

"Right. I'll just..." He gestures towards the punching bag and goes to pick it up. The girl lingers for a moment before she moves to help, sweeping up the spilled sand with a broom she finds in a corner. He thanks her before grabbing his duffel bag of equipment and leaving the gym. He's caught by Director Fury in the hallway and doesn't notice the girl stopping her own training to listen in.

* * *

"I just keep running into you," Steve jokes as he approaches the girl on the helicarrier and she jumps, turning sharply and only relaxing when she sees that it's him.

"You ought to wear a bell. Someone as tall as you shouldn't be allowed to sneak around." Still, she smiles for the first time that Steve can remember, relaxing a little. "I'm on monitor duty." She nods to the computer in front of her.

"Seriously, how old are you?" Steve prompts again and the girl huffs.

"Seventeen, but don't tell Fury that." She types in a few lines of code that go over Steve's head before turning back to him.

"Really?" Steve raises an eyebrow back at her.

"It's not entirely a lie, mind you, I turn eighteen next week," she retorts and Steve supposes he can understand that. If the war had started when he was seventeen, he would have thrown himself headfirst into it.

"Your secret's safe with me," Steve tells her and she gets an unreadable look on her face before she smiles and mockingly salutes him.

Steve asks Agent Coulson about her later and has to describe how she looks before the other man recognizes whom he's referring to.

"We just call her Agent 20, makes it easier. She doesn't use a name, she signed up straight out of an orphanage in New York."

"So she was never called anything? Ever?" Steve finds that hard to believe, but he only gets a shrug from Coulson in return.

* * *

He doesn't see Agent 20 until after the helicarrier is attacked, and he finds her nursing a split lip in the conference room.

"Hey." He sinks into a chair beside hers and for once, she doesn't flinch.

"Hello, Ca - Steve," she corrects herself and looks relieved by the tired smile Steve manages to give her.

"You okay?"

Agent 20 shrugs. "I've had worse." Steve eyes her warily and a tiny pink flush appears on her cheeks. "I _have_ ," she mumbles defensively and Steve raises his hands in surrender. They both lapse into silence for some time and after a few moments, Agent 20 prompts quietly, "Did you know him? The man who died?"

"Agent Coulson?" She nods and Steve frowns, glancing at the table and shaking his head. "Not well, no."

"Same." Agent 20 is silent again after that and Steve looks up at her to find her looking at her own hands. "He was nice, though," she says, her voice barely above a whisper.

"Yeah." Steve doesn't know what to say to that, so they just sit in silence again until Fury comes in with a few bloodstained Captain America vintage cards and a very rehearsed-sounding speech.

Agent 20 requests - no, _demands_ \- to go down to New York with Steve, Clint, and Natasha. Steve doesn't see the harm in letting her come along, but he doesn't miss the sharp, mistrustful stare Natasha is giving the girl. He figures she has no room to judge; she's vouching for Barton, after all, even though he had just tried to kill them all barely an hour earlier.

* * *

After the battle, Steve hardly remembers any of the actual fighting.

There are flashes that stick out in his mind - Natasha closing the portal, the Hulk quite literally scaring Tony back to life, taking Loki into a specialized prison cell to wait until they figure out how to send him, Thor, and the Tesseract back to Asgard - but only a few moments in the actual battle stand out to him. One of those moments is when he is surrounded by Chitauri, two on his six and three in front of him, and Agent 20 suddenly calls over the comms for him to get down.

By instinct, he does, and within seconds, all five Chitauri drop like flies. Steve rolls to his feet and sees Agent 20 on a low rooftop above him, reloading a sniper rifle that she had gotten from God knows where. He salutes her mockingly and only has time to see the smile on her face before he throws himself back into the fray.

He doesn't see her pulling a second earpiece out of her ear and stomping it to pieces.

She nudges her shawarma over to him after the battle, whispering under her breath so that only he could hear that she's allergic to the sesame seeds in tahini, which Steve realizes the shawarma is topped with.

"Why didn't you tell anyone?" Steve whispers back to her, making sure to keep his voice low so that no one else sitting around the table hears. "We could've gone someplace else."

Agent 20 flushes a little with embarrassment. "I didn't want to make a big deal out of it. And everyone else wanted shawarma."

Rolling his eyes, Steve swaps her shawarma for the large container of french fries in front of him and she smiles gratefully before taking a fry to nibble on. Conveniently, everyone else is too exhausted from the battle to notice the exchange, but Steve does notice Natasha still staring at Agent 20 skeptically.

* * *

It takes approximately two days for them to get Thor, Loki, and the Tesseract back to Asgard. Steve doesn't actually see Agent 20 much in that time, as she actually spends a lot of time down in the lab with Tony and Bruce. They both seem to get along with her well, especially when she expresses her interest in computer programming. Tony practically lights up at that, rambling on about different languages and syntax and which would suit her current level of knowledge best.

It's with an overwhelming sense of relief that Steve sees Thor off, the rest of the Avengers - if what Tony called them is actually their team name now - beside him. Once the Asgardians and the Tesseract are gone with only a scorch mark on the ground left in their wake, they begin to pair off. Clint and Natasha depart together while Tony and Bruce get into a red convertible to drive back to Stark Tower, which is still under construction.

Steve begins walking to his motorcycle to head back to his SHIELD-issued apartment and pack up to head down to D.C., but stops as he reaches the end of the sidewalk. He turns to see Agent 20 still standing where they had left her, shuffling a little on the spot and looking somewhat lost and uncertain.

"Hey." She starts, looking up from the ground she had been studying intently. "You coming or what?" She stares at him for a moment, confused, but when he holds up the spare motorcycle helmet, her face breaks into the widest smile he thinks he's ever seen as she nods and closes the space between them to take the helmet.

She's still grinning broadly even as she gets onto the motorcycle behind him, arms tight around his waist as he starts the motorcycle up and begins driving back to his apartment.

* * *

Steve admits, in retrospect, that maybe it had been a rash decision to just take Agent 20 with him to his - _their_ \- new apartment in D.C., but he doesn't regret it, especially when he sees the stunned look on Agent 20's face when he opens the door to the apartment and says, "Welcome home."

SHIELD agrees to take care of the paperwork, as the girl had been a ward of the state before Steve had taken her to D.C., and she now needs a legal guardian, at least until the following week. Agent 20 doesn't hesitate to agree the moment Steve offers to put his name as her legal guardian, but she does hesitate when he tells her she needs a name.

"You can't just call yourself Blank Rogers," Steve says dryly, which earns an amused snort from Agent 20.

"Well, that's _one_ possibility."

"We're not naming you Blank," Steve insists and Agent 20 just laughs.

"Let's call her Fluffy," Tony says cheerfully when Steve calls him to inform him that Agent 20 will be living with him.

"She's not a pet, Stark." Despite his stern tone, Steve's grinning; Tony really isn't so bad once Steve's gotten used to his sense of humor.

"Seriously, Capsicle. She's your kid now. Name her whatever you two can agree on."

His kid, Steve muses once he's hung up on Tony. He thinks he can live with that.

* * *

Steve and Agent 20 come to a consensus on the name and the paperwork is filed. He's told by Agent Hill that the adoption certificate will arrive in the mail in less than a week. It occurs to him only then that he doesn't know when exactly Agent 20's birthday is.

It turns out he doesn't have to ask. The following Wednesday, Agent 20 shuffles into the kitchen, which is now fully stocked, and gets herself a glass of apple juice. Steve's discovered she prefers it, so he keeps the orange juice for himself.

"It's my birthday," she mumbles, as if afraid of being punished for voicing it, and Steve smiles, thinking inwardly that it was a good thing he had bought wrapping paper and wrapped his present for her the previous evening.

"Happy birthday." He squeezes her shoulder and she stares at him for a moment before hiding her smile into her glass of juice. Steve sends a quick message to Tony and Bruce, glad that he had learned how to text a few days earlier. Neither of them respond.

Later that afternoon, Steve goes out to the nearest bakery he can find and gets a small chocolate cake with chocolate frosting and blue icing letters spelling out "Happy Birthday." He hides it in the fridge until that evening, when the doorbell rings.

Agent 20 opens the door, frowning at the package on the doorstep.

"Steve?" she calls nervously and Steve laughs when he sees the neatly-wrapped large box on the floor covered in red wrapping paper adorned with cartoonish Iron Man helmets and a ridiculously large gold bow on top.

"It's from Stark," he reassures her, picking it up. "And it's for you."

"For me?" Agent 20 echoes, blinking.

"Yeah. He must have gotten it after I told him it was your birthday this morning." Steve carries the present inside and sets it on the counter. "Tell you what, you can open it and my present after dinner."

"You didn't have to get me anything," Agent 20 hurries to insist and Steve just rolls his eyes, ruffling her hair affectionately and earning a yelp of protest as she straightens her hair out.

"Go wash up, I'll order pizza." She perks up at that, the idea of presents forgotten as she goes to wash her hands before dinner.

After they eat dinner and the leftover pizza is stored in the fridge, Steve brings out the cake with a single lit candle. Agent 20 stares at the cake as he puts it down in front of her, her blue eyes wide and bewildered.

"What's this for?" Her voice wobbles dangerously and Steve thinks, perhaps a little belatedly, that he has no idea how to comfort her if she starts to cry.

"No birthday's complete without a cake. Come on. Make a wish and blow the candle out." She stares at the flickering candle for a moment before swallowing and then blowing it out. They each eat a slice of cake before putting the rest away for another day, and Steve retrieves her presents so she can open them.

Tony and Bruce had sent two boxes within the first one. Tony's box is wrapped in even more ridiculous Iron Man wrapping paper while Bruce's box is wrapped in a more subtle green wrapping paper - although Steve is convinced Tony had a very strong hand in choosing that paper for Bruce, too. Agent 20 opens Tony's box first to find a pile of books on programming languages along with an electronic tablet.

"Awesome," she blurts out the moment she sees them, positively beaming as she pulls the books out to examine each title before picking up the tablet to study it curiously. Remembering that she has other presents, she sets Tony's gifts aside reluctantly to open Bruce's present, which is a stuffed wolf toy. With a small laugh, she pulls it out of the box and pets its small head before hugging it close. "I should call and thank them," she says quietly, face half-buried in the wolf's soft fur. "Nobody's ever given me anything like this before."

Steve feels his throat tighten a little at that, but he just clears it and nudges over his present to her. She sets the wolf down and picks up the present, tearing open the simple blue wrapping paper and pulling out the large yellow envelope. She frowns up at him and he just nods to it. She opens the envelope, staring at the piece of paper that's inside with wide eyes.

"I guess we can stop calling you Agent 20 officially," Steve says after giving her a moment to process what was on the paper. "Happy birthday, Sarah Margaret Rogers." He barely has time to notice the tears welling up in Agent 20's - no, _Sarah's_ \- eyes before she flings herself into his arms and hugs him tightly.

* * *

Steve visits Peggy on his own the first few times, but he starts bringing Sarah after a while. Peggy starts to cry when Sarah shyly introduces herself as "Sarah Margaret," and Sarah can't do much more than sit there, flabbergasted, and awkwardly pat Peggy's wrinkled hand. Peggy eventually dries her eyes and reassures her that, no, of course she's not upset, she's just very flattered and thinks that if anyone deserves to be named partially after her, it's Sarah, which makes Sarah turn bright red and smile widely.

Peggy insists that Steve step out to get her a glass of water, which Steve doesn't hesitate to do, and makes Sarah quietly promise to take care of Steve for her. Sarah promises solemnly and Peggy gives her a tired smile, patting her hand.

Within an hour, she forgets who Sarah is and that Steve's alive, and Steve's voice cracks as he repeats the same words he'd used when they had first come in. Sarah presses quietly against his side and he lets out a shuddering breath of relief even as he forces a smile for Peggy's sake and wraps his free arm around Sarah's shoulders to ground himself.

* * *

They settle into a routine.

Steve discovers that Sarah seems to be just as out of touch with pop culture as he is - and when he teases her, she just gives him a withering look that makes him shut up instantly - so they hold movie marathons together. When he pops in Snow White on a whim, she perks up at the sight of the colorful animation and melodies, so he begins putting on more Disney movies from then on.

Sarah soon starts singing quietly to herself after that, usually songs from whatever Disney movies they had seen the previous night, and Steve starts drawing again. Sarah likes his art and asks to see it often, but flushes and draws back into herself whenever he mentions her singing in turn. He doesn't tease her about it much after that, and if he hears her singing from then on, he doesn't acknowledge it.

They go running in the mornings together, and Steve usually outruns Sarah at least by two laps every time. She calls him a show-off.

They do freelance work for SHIELD once in a while, taking missions whenever Fury deals them out. Natasha sometimes joins them on missions, eyeing Sarah distrustfully the entire time. Sarah either doesn't notice or doesn't care. She is almost frighteningly efficient on missions, cold and precise and single-minded and reminding Steve somewhat of Natasha.

He thinks sometimes that maybe Natasha is right to be skeptical of her, but then they get home and clean up and Sarah curls up against Steve's side while they put on another Disney movie and Steve decides Natasha is, for once, wrong.

* * *

Steve and Sarah usually don't come across other joggers on the path they take, but one morning, they pass a man jogging. Sarah may not be as fast as Steve, but Steve still hears her overtake the other man with a cheeky "on your right." To add insult to injury - because Steve isn't above that, he _really_ isn't, and who could resist such an opportunity? - he jogs ahead to overtake the man again, grinning as he adds innocently, "On your left."

"Come on!" the man yells in frustration after Steve passes him and Sarah two more times, and eventually he and Sarah end up sitting on the grass together to catch their breaths and wait for Steve to join them.

Sarah glowers at Steve dully when he walks up to them, not even out of breath, and he shrugs at her apologetically. She seems to have made peace with the other jogger, who accepts Steve's hand to help him up.

His name is Sam Wilson and he had spent two tours overseas flying pararescue. He obviously knows who Steve is, and Steve introduces Sarah as his daughter, realizing absently that it's the first time he's called her that.

Even as Natasha picks them both up for a mission, Sarah doesn't stop smiling.

* * *

Steve's angry - angry at Natasha for going behind his back, angry at Sarah for practically throwing herself between him and Batroc so that she could catch the bomb that Batroc had thrown and toss it away, and angry at Fury, especially, for creating a divide in their rescue operation where there needn't have been.

After they get home and clean up, Sarah curls up against Steve's side, her hair still damp from her shower as Steve puts on The Lion King, the next on their list of movies to catch up on. She watches it quietly, not adding comments like she usually does, and only speaks when the credits are rolling.

"This one's my favorite."

Steve's partial to the older Disney films, but he can't help but agree. Sarah smiles when he confirms it, and she soon falls asleep against his side. Steve doesn't have the heart to move her to her bed, so he just puts his head on top of hers and soon drifts off to sleep as well.

* * *

Sarah stays at home the next day instead of going out jogging with Steve, which Steve doesn't really mind. He goes to the Triskelion to confront Fury while Sarah's not with him, visits Sam at the VA and Peggy at the nursing home in that order, and then goes back home to make sure Sarah's eaten.

She hasn't, so he takes her out so that they can get lunch together. For all her reticence around other people, Steve notices that Sarah has no qualms about making him uncomfortable, as she insists they go to the new Captain America exhibit that has opened in the Smithsonian museum and eat at the cafeteria there. So Steve tugs a baseball cap over his face and they go to the museum.

Sarah giggles for the first ten minutes once they enter the exhibit, taking a jarringly vindictive pleasure in pointing out every single image of Steve's face that she can see on the walls of the exhibit. She finally goes quiet when Steve begins to actually look around, probably sensing the change in his mood, and presses against his side wordlessly as he leads her through the exhibit.

He stops in front of Bucky's display and she does, too, staring up at the image on the wall with an unreadable expression on her face.

"Was he your friend?" she asks softly, even though it says so on the first line itself.

"Yeah." Steve's voice cracks slightly and she tilts her head so that she can peer under his cap.

"More than that?" she prompts, a knowing edge to her voice, and Steve shakes his head.

"Wasn't legal back then."

"Oh." Sarah looks between the display and Steve before nudging him gently. "I'm sorry for your loss. I don't think I've ever said that before about...well, anything, so I guess that's overdue."

"'S okay." Steve manages a smile at her before leading her away from the exhibit before he can break down right then and there. "Come on, I hear the mac and cheese in this place is actually good."

* * *

It's late at night when they get back to their apartment, and Steve stops to talk to their neighbor, which quickly evolves into awkward flirting. He sees Sarah roll her eyes before stiffening out of the corner of his eye, and it's then that their neighbor points out that his stereo's on. Steve glances at Sarah, who's already heading for the fire escape, before thanking their neighbor and following Sarah.

They enter through the kitchen window and Sarah goes ahead even as Steve grabs his shield. He sees her shoulders lose their tension the moment she enters the sitting room.

"It's okay, Steve, no hostiles."

"Depends on what you consider hostile," Fury's voice answers dryly, sounding strained, and Steve rounds the corner to see Fury sitting in an armchair, clearly injured.

Sarah leans against the sitting room window, her posture relaxed, but her expression pinched with concern. "Are you going to explain why you're so banged up?" she prompts and Fury shakes his head, putting his finger to his lips in the universal "shh" gesture. Getting the hint, Sarah goes quiet.

"My wife kicked me out," Fury tells Steve calmly.

"Didn't know you had a wife," Steve answers skeptically.

"A lot of things you don't know about me," Fury answers cryptically.

"I know, Nick, that's the problem," Steve says in frustration, moving to turn on the lamp since they're all sitting in the dark. Fury promptly turns the lamp off again before typing a silent message on his phone screen and showing it to Steve.

 _Eyes and ears everywhere. SHIELD compromised_.

Steve swallows, saying quietly, "Sarah, move away from the window." He can't take a chance with Sarah being in danger, and he sees her raise an eyebrow, but obediently move away from the window. "How many people know about your wife?" he asks Fury.

"Just my friends," Fury says as he pushes himself to his feet.

"Is that what we are?" Steve says sharply.

"That's up to you." Suddenly, three sharp gunshots ring out, shattering the window Sarah had just moved away from as Fury collapses.

Steve rounds on Sarah to make sure she's out of the line of fire, only to see that her face is pale, her lips bloodless and her eyes wide. She hurries to look out the window and before Steve can yank her back out of the line of fire, she breaks into a run, racing out the front door.

"Sarah!" Steve can't go after her when Fury is bleeding out on the floor, though, so he forgoes running after her to drop to his knees beside Fury. When he finally goes after the shooter, though, he finds the man on a rooftop, Sarah in front of him. Before he can wonder how Sarah had gotten to the man before he had, he notices that Sarah's speaking to the man in a foreign language - Russian, Steve realizes after a moment - with a low and desperate voice, her hands held out placatingly.

The man's eyes are fixed on her, so Steve acts quickly, throwing his shield hard to catch him off-guard. The man's attention diverts when he hears it and he catches the shield quickly, his palm making a sharp clanging sound as the shield makes contact with it. It's then that Steve realizes his arm is made entirely of metal.

Sarah whips around, her wounded expression aimed at Steve, but then the man throws the shield back so hard that Steve skids a little when he catches it. Sarah cries out something in Russian again as the man jumps over the edge of the rooftop and when Steve makes it to the edge to look, the man is gone.

* * *

Steve doesn't ask questions until after they've taken Fury to the hospital and he dies on the operating table. While Natasha is silently mourning the man in the other room, Steve takes Sarah aside.

"How do you know him?" he demands and she just stares at him, her eyes wide and hurt the same way they had been since he had chased the man away. "Who is he?"

"No one. Just an assassin." Her eyes dart to the side, though, unable to meet his, and he knows instantly that she's lying. "I don't know him."

He wants to push her, but the memory of the flash drive distracts him as he reaches into his pocket to pull it out. "Fury gave me this. Do you know why?" She shakes her head and looks relieved when Natasha comes out of the room, her eyes suspiciously wet. Steve hurriedly stows the flash drive in his pocket again.

"Why was Fury in your apartment?" Natasha demands as she comes up to him.

"I don't know," Steve lies. Fury had told him to trust no one, so he would take that advice at face value.

"You're a terrible liar," Natasha says after a moment, managing a smirk before she walks away. Before Agent Rumlow can come to collect Steve and take him to the Triskelion for questioning, Steve quickly stows the flash drive in the nearest vending machine behind several packs of bubblegum.

Sarah finally cracks a tiny smile as they begin walking down the hall. "You realize you're essentially counting on nobody buying bubblegum, right?" Steve's not in the mood for jokes now, though, especially when he remembers how familiar Sarah had seemed with the man on the roof, and her smile slips when she notices his mood. She doesn't speak again for the entire ride to the Triskelion, but Steve still notices how her eyes are trained on Rumlow suspiciously like Natasha's eyes are usually trained on her.

He doesn't question it, too angry and confused to do much else than sit quietly.

* * *

Sarah is giving Senator Alexander Pierce the same look she had given Rumlow and Steve doesn't like it. Confused as he is by her, he knows better than to mistrust her judgment, so he makes his excuses and leaves Pierce's office with a hand on her shoulder. She's tense as they get into the elevator and are soon joined by Rumlow and several other bulky men, some in suits and some in SWAT gear. Steve squeezes her shoulder reassuringly as they're packed into the middle of the elevator and her hand reaches up somewhat hesitantly to squeeze his hand in return. It gives him a little comfort knowing she's not angry with him for the way he's treated her recently.

Once all the men are unconscious, Steve grabs her and jumps out of the elevator, shattering the glass as they plummet down to the main lobby of the Triskelion. It's a credit to whatever Sarah had been through in her past that she doesn't scream as Steve angles them around so that she's tucked against his chest, his shield beneath them. They crash through the glass roof onto the floor of the lobby and Sarah rolls to her feet, grabbing his hand to pull him up as they start running for the garage.

They narrowly avoid a large jet preventing their escape, and it's only after they reach the hospital again that Steve gently tugs her aside. Her shoulders tense up as her breathing picks up, her eyes narrowed and fixed on him.

"I'm sorry," Steve says finally and Sarah's shoulders loosen a little, but she still keeps her jaw tight and her chin up. "You were right about Rumlow. And Pierce. And I'm sorry I didn't trust you."

"'S okay," she mumbles at last, her voice hoarse from not speaking since they had left the hospital earlier. "I wouldn't've trusted myself either, considering the guy who shot Fury is my dad."

Steve blinks at her. "What?"

"I _knew_ it," Natasha says triumphantly behind them and Steve jumps, turning sharply to face her. She blows a neon pink bubble and snaps it and Steve checks the vending machine hurriedly.

No flash drive.

He turns sharply and grabs Natasha's arm, dragging her through the nearest door into a small room. Sarah hurries after them as Steve shoves Natasha against the wall.

"Where is it?" he demands, but Natasha's still staring at Sarah smugly.

"I _knew_ there was something off about you. You're the Winter Soldier's daughter." Sarah's lips purse a little as she drops her gaze to the floor and Steve pushes Natasha's shoulder again to get her attention.

"Who's the Winter Soldier?"

"He's a ghost story," Natasha supplies. "Most of the intelligence community doesn't believe he exists. But he's real and he shot Fury. And apparently has a kid."

Steve sees Sarah turn red with a mixture of embarrassment and anger.

* * *

Steve finds himself walking side by side with Natasha in a mall, wearing the most uncomfortable shoes he can ever remember wearing and a dark hoodie along with glasses. Sarah is ahead of them, her expression pinched as she rounds the corner and goes to the nearby Baskin Robbins. Steve goes to follow her, but Natasha grabs his arm and steers him into the Apple store instead.

"Relax, she can handle herself if she's who she says she is," she says flippantly and Steve glowers at her mildly as she goes to a demo computer to set up the flash drive.

"It's not her fault she's kept it quiet all this time when you've been breathing down her neck since day one," he reminds her and she just rolls her eyes.

"I was right to, wasn't I?" Steve has no answer as she plugs in the flash drive and sets to work.

Nine minutes later, flash drive in hand and location acquired, they get out of the store and Steve sees SHIELD agents everywhere, including Rumlow coming down the escalator.

"Sarah," he says suddenly, realizing she's alone and unarmed to defend herself, and Natasha grabs his hand before he can run to Baskin Robbins.

"She'll be fine," she insists, her expression softening a little. "She'll catch up to us. Follow my lead, we'll need to lose them." She tugs him to the escalator.

To her credit, Sarah does find them just outside the mall a few minutes after they lose the agents, sipping on a blended coffee and ice cream concoction that looks far too sweet to be remotely healthy. One look at her still pinched expression keeps Steve from nagging her.

* * *

While they drive to New Jersey, Steve can see Sarah nursing her drink in the backseat of the truck they had stolen, her lips still pressed together in a tight line like they had been ever since Natasha had joined them in the hospital.

"I'm sorry I didn't tell you." Steve nearly jerks the wheel in surprise at the sound of her voice after nearly an hour of silence, but steadies it again, not responding even as Natasha's sharp green eyes focus on Sarah in the rearview mirror. "I should've, I know. It just never seemed important until now."

"Never seemed important?" Natasha echoes before Steve can answer. "You're the daughter of one of the most dangerous assassins in the world and-"

"I'm not his daughter," Sarah interrupts before flushing. "I mean, strictly speaking, we're not... _naturally_ related or anything. I'm a test tube baby, I was created from his DNA. They wanted to remake him. So here I am." She shrugs one shoulder.

"For all intents and purposes, biologically, he's your father," Natasha answers simply.

Sarah sighs a little, dropping her gaze to her knees. "I guess."

"Who's 'they?'" Steve asks at last and Sarah only shakes her head.

"I don't know. I'm sorry," she repeats. Steve wants to tell her it's okay, but one look at the apprehensive expression on Natasha's face keeps him quiet as he drives, and he does his best not to hear the tiny sniffle from the backseat.

* * *

They're all battered and bruised and covered in dust from the explosion. Natasha is laying down in the backseat, sleeping off the head injury she had received, and Sarah is sitting in the passenger seat as Steve drives back down to D.C., his blood boiling with how angry he is.

 _Fucking_ HYDRA. Even after he's lost everything, they're _still_ around.

Sarah coughs a little and Steve comes back to the present, realizing he's clutching the steering wheel so hard that the wheel is creaking under his fingers. He loosens his grip and looks over at Sarah only to find her staring out the window with the same wide-eyed horrified expression she's had ever since Zola had spoken directly to her.

 _"You were our magnum opus. Project Winter Rebirth."_

 _"You took your training so well, and you responded perfectly to orders. It was only when you failed to eliminate Captain America that we realized you were not our greatest success, but our greatest failure."_

Steve does his best not to squeeze the steering wheel again, but his stomach twists unpleasantly when he thinks about how Sarah could have killed him at literally any time in the past year since New York. Maybe Natasha had been right about her all along.

* * *

While Natasha showers at Sam's place, Steve finds Sarah toweling her hair quietly as she sits in a chair in Sam's kitchen. Sam is making pancakes, Steve notices absently, flipping them while keeping a close eye on both of them.

"About what Zola said," he speaks up after a moment and Sarah's shoulders tense. "When were you assigned to, uh, _eliminate_ me?"

Sarah's gaze remains downcast, fixed on her knees as she answers, "I got my orders when you were found alive in the ice." She swallows. "My...my orders were to get into SHIELD as an agent and then eliminate you when the time was right." Steve's chest feels tight even as she continues, "Those were the general mission parameters. When we all went down to New York, when the Chitauri invaded, I received orders to take you out then, so we could cover it up quickly."

She looks up at him at last, her blue eyes swimming, and he has to look away before his chest gets any tighter. He doesn't think he's ever been this close to the sensation of an asthma attack since before the serum.

"But you didn't," he croaks out after a moment and notices that Sam has stopped moving in the background.

"You might remember at one point, I took out five Chitauri surrounding you." Sarah swallows before she adds, "I had a second earpiece for communication with HYDRA. They were ordering me to take you out with a single shot then and there, and I went against orders."

Steve manages to force himself to look at her, managing to get out, "Why?"

Sarah's voice wobbles when she answers, "You were kind to me." She drops her gaze back to her knees, the tears in her eyes falling and darkening the fabric of her jeans from blue to black where they landed. "No one had ever been kind to me before. And you were. So I figured...I figured you couldn't be as bad as they made you seem," she finishes in a rush of breath and Steve's chair scrapes harshly against the tile floor as he pushes it back.

Sarah flinches as she looks up at him, her eyes wide and wet. Steve gets out of his chair and kneels in front of hers so that they're at eye level before dragging her into a tight embrace. Sarah shudders a little against him before pressing her face into his shoulder, her own shoulders trembling. As he feels his shoulder steadily getting more damp, he looks up to see Natasha leaning on the doorway and watching them, her expression pensive as she towels her own hair dry. Sam is silent, but thankfully resumes making breakfast again instead of saying anything.

* * *

Sarah is eyeing Jasper Sitwell with the exact same look she had given Rumlow and Pierce, so Steve definitely knows they have the right guy. With Zola's algorithm revealed, they're now on the road in Sam's car to head back to his apartment and reformulate a plan.

A plan which needs to be even more quickly reformulated as a metal hand grabs Jasper Sitwell and throws him out the window into heavy traffic.

Sarah, who hadn't screamed when Steve had thrown himself and her out an elevator several stories high, shrieks as the same metal hand tears out the steering wheel of Sam's car, causing it to careen out of control. Steve grabs her from the backseat as well as Natasha, hauling them and Sam close as the door they're leaning against breaks off from the car. They skid across the asphalt and Steve can see a cut on Sarah's forehead bleeding as she stumbles to her feet, wide eyes fixed on the Winter Soldier in fear.

Steve doesn't have time to get up when a grenade is launched at him, giving him only time to shield himself as he's tossed over the edge of the overpass into a bus below.

When he comes to, HYDRA agents have swarmed the street as well as the overpass above, and the Winter Soldier is going after Natasha and Sarah. Steve breaks out of the bus and grabs his shield from the road before breaking into a run just as he sees the Winter Soldier shoot Natasha's shoulder. Natasha crumples and Sarah grabs her immediately, pulling her out of sight. As the Winter Soldier goes towards their car, Steve rushes forward to take him on.

At some point, he throws the Soldier so hard that the mask cracks and falls off the man's face. As the Winter Soldier stands, Steve's breath leaves him as he stares at the familiar face.

"Bucky?" he croaks and the Winter Soldier - _Bucky_ \- just stares at him, eyebrows slowly knitting together in confusion, before lifting his gun to fire.

"No!" Sarah races between them, her hands bloody where she had been tending to Natasha's shoulder as she holds them up, facing Bucky with her jaw clenched and her chin held up. "Don't!" The Winter Soldier croaks something in Russian, to which she quickly responds in English, "No. I know my place now. It's between HYDRA and him."

Steve half-wishes he doesn't feel like his world is crumbling around him right now or he would probably hug her. "Bucky," he says weakly again, stumbling forward, and this gets their attention.

"Who the hell is Bucky?" the Winter Soldier says blankly and Sarah glances at Steve before her eyes widen and she turns back to look at the Winter Soldier. She opens her mouth to say something, but then a grenade is launched between them, causing an explosion on the street. Both Steve and Sarah shield their eyes, and when the smoke clears, the Winter Soldier is gone.

* * *

"Did you know?" Steve says quietly when they're at the bunker, Natasha's shoulder getting tended to while she and Fury catch up. Sam is getting briefed by Agent Hill, and Steve and Sarah are alone outside on the bridge overlooking the backwaters of the Potomac. It's finally starting to sink in now, the implications of Bucky being the Winter Soldier.

"No," Sarah says immediately, shaking her head. "I had no idea, I swear." She looks him in the eye this time, but he's too angry - at HYDRA, at the unfairness of Bucky being alive and brainwashed, at _her_ \- to believe her.

"Like hell." She recoils like she's been hit, but Steve's seeing red now. "You saw his face in the museum. You're telling me you never once recognized them as the same person?!"

"I haven't seen his face without the mask in a long time," Sarah insists and slowly, the fight drains out of Steve despite how much he wants to cling to it. Anger's good, he's familiar with anger, not all of...whatever this is. "I was very young the last time we interacted, maybe two." She swallows. "I haven't seen him outside of missions after that until that night at our apartment."

"What happened then? When you saw him last time?" Steve manages after a moment.

Sarah looks out at the river, chewing her lip. "They had me working with alphabet blocks, I think. I remember him coming to sit with me, but he didn't say anything, just watched me sort the alphabet out. Then he was taken away." She falls silent and Steve is angry again, but not at her anymore.

"We'll get him back," he vows quietly and she nods, surprising him.

"We'll get him back," she repeats.

* * *

Steve wakes up in the hospital aching all over and feeling like he's been shot several times and beaten to a bloody pulp.

He turns his head slightly when he hears Marvin Gaye's _Trouble Man_ playing and sees Sam reading a book while sitting in a chair in the corner of the room. Closer to the bed is Sarah, whose hand is slipped into his own with her head pillowed on the edge of the bed.

Steve grimaces at how uncomfortable she has to be before managing to croak out, "On your left."

Sarah jolts awake as Sam looks up and grins, and the first thing she does is burst into tears and launch herself at him even as Sam warns her not to. Steve hauls her close without hesitation and, to his credit, doesn't flinch once whenever she accidentally hits a sensitive spot with her sharp elbows.

In the following weeks after the fall of SHIELD and Steve's release from the hospital, Steve supposes that a lot of things are making more sense now. It makes sense why Sarah's vivid blue eyes are so achingly familiar - _Bucky's_ \- as well as her smile - _definitely Bucky's_ \- and the way her voice wobbles right before she's about to cry, which Steve definitely remembers that Bucky's voice used to sound the same on the rare occasions he cried.

She tells Steve that she's the one who found him on the bank of the river after the helicarriers crashed, but Bucky had been nowhere to be found. Steve tries not to be disappointed, but Sarah knows better. She tells him she's lived with him too long to not notice the sad puppy face, whatever that means.

Every single Avenger sends him a cheesy get-well card, and Tony even sends a ridiculous bouquet of multicolored flowers.

Sam becomes an almost-permanent staple in their apartment once Steve's released, coming over frequently for meals and just to talk to both of them, which Steve thinks Sarah appreciates. He knows he isn't much company for her since he sees Bucky in everything she does now and she knows it.

He leaves her at home when he and Sam begin searching for Bucky, but at her request. She isn't sure she's ready to face Bucky yet, which Steve can understand. Even if Bucky remembers who he is, Steve himself isn't sure if Bucky's ready to face his past as the Winter Soldier yet, either.

* * *

They bring Bucky home after months of cold leads and searching, and he stops dead in his tracks when he sees Sarah sitting on the couch watching The Lion King. She pauses the movie when she looks up and spots him, swallowing and slowly getting to her feet.

"I can go," she blurts out when Bucky opens his mouth to say something. "If I make you uncomfortable."

Steve opens his own mouth to protest but Bucky beats him to the punch, his voice hoarse with disuse as he croaks, "Don't be stupid. You live here, too."

Sarah shuffles a little awkwardly, her gaze dropping to the floor, and Sam makes his excuses and leaves. Steve figures this should be between the three of them, anyway, so he doesn't stop Sam.

"Are you hungry?" he offers and Bucky turns his head to stare at him, bewildered, before shaking his head. He takes a tiny step towards Sarah, who flinches, before stopping again, eyebrows knitting together with concern. She wordlessly shakes her head and before Steve can ask about their silent exchange, she closes the gap between them to place her arms tentatively around Bucky's torso.

Both Steve and Bucky freeze, Bucky's metal hand awkwardly hovering over Sarah's back as Steve tenses in preparation to pull her away in case Bucky snaps, before Bucky slowly places both arms around Sarah in return, letting out a shaky sigh as he places his cheek against the top of her head. He murmurs something in Russian and Sarah lets out a tiny hiccuping sob before she replies in Russian as well and burrows into his chest.

Steve decides he needs to learn Russian soon.

* * *

"I should change my name," Sarah muses as they watch Frozen. It's been three months since Bucky moved into the apartment, and he's improved by leaps and bounds since then. There are still bad days, but recently, there are more good than bad, and Steve's okay with that.

Even if Sarah calling Bucky "Papa" once in a while makes something in his chest twist with jealousy.

"Well, that makes sense. Your biological dad's here, so you should change your last name to Barnes sometime," he reasons, keeping his voice light even though his throat tightens at the thought. _No more Sarah Margaret Rogers_ , he thinks dolefully.

Sarah scoffs, breaking him out of his thoughts. "Don't be dumb, _Dad_. I just meant I should add both your last names to mine."

"Add?" Steve echoes, taken aback by what she had just called him, and Bucky snorts with amusement.

"Yeah, Stevie, _add_. Keep up." Steve throws him a dry glare.

"Yeah. Like Barnes-Rogers or vice versa." Sarah shrugs as she explains. "You two might as well be married as it is, so I'd have to change my last name eventually, anyway."

Steve sputters a little, but Bucky throws his head back and _roars_ with laughter, Sarah soon joining in with a small giggle of her own. Steve looks over her head and sees Bucky grinning back at him broadly, something soft and warm in his eyes, and...yeah.

Sarah Margaret Barnes-Rogers had a pretty nice ring to it.

* * *

 **This is literally the longest single-chapter fic I've ever written, but I've had this idea in my head for so long that I _had_ to get it out of my head, and since the snippets were so small, I didn't want to turn it into a multi-chapter story. Please enjoy!**

 **(Also, The Last Airbenders _is_ coming soon, so don't review this fic asking for the next chapter of that one or any of my other stories. Please review only if you're going to review this fic.)**


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